Method and apparatus for web edge alignment

ABSTRACT

A sensor for controlling the edge position of a moving web wherein a finger rides along the edge being sensed and the position of the finger is used to control an air valve to develop fluid control signals indicative of edge position. One surface of the web moves across a backup plate or roller and the other surface of the web is provided with a tracking roller opposite the backup plate. The tracking roller is pivotable in a plane substantially parallel to the movement of the web. The fluid pressure from the air valve is used to pivot the tracking roller in response to web edge position thereby maintaining the web edge in a desired location. The apparatus includes a transport device for applying articles to the surface of the web and for folding the web to confine the articles therein. Sensors and tracking rollers are disposed on opposite sides of the machine and constantly sense and constantly adjust the edges of the moving web. The sensors are provided with an eccentric mounting to adjust the web height at which each sensor begins to operate its associated air valve.

United States Patent Vogelet a].

[451 Mar. 28, 1972 [54] METHOD AND APPARATUS FOR WEB EDGE ALIGNMENT [72] Inventors: Walter H. Vogel; Richard H. Cochrane;

Robert C. James, all of Sheboygan, Wis.

[58] Field oiSearch ..226/3,2l23,45; 26/63, 67; 270/52; 156/324, 361, 433, 459, 306,

[56] References Cited UNITED STATES PATENTS 1,739,993 12/1929 Tandel....l ..26/67 2,938,720 5/1960 Mittag ..226/23 3,013,513 12/1961 Judelson ...226/23 UX 3,147,898 9/1964 Huck ..226/2l X 3,371,916 3/1968 Jaeger ..226/l7 Primary Examiner-Richard A. Schacher Attorney-Hill, Sherman, Meroni, Gross & Simpson [57] ABSTRACT A sensor for controlling the edge position of a moving web wherein a finger rides along the edge being sensed and the position of the finger is used to control an air valve to develop fluid control signals indicative of edge position. One surface of the web moves across a backup plate or roller and the other surface of the web is provided with a tracking roller opposite the backup plate. The tracking roller is pivotable in a plane substantially parallel to the movement of the web. The fluid pressure from the air valve is used to pivot the tracking roller in response to web edge position thereby maintaining the web edge in a desired location. The apparatus includes a transport device for applying articles to the surface of the web and for folding the web to confine the articles therein. Sensors and tracking rollers are disposed on opposite sides of the machine and constantly sense and constantly adjust the edges of the moving web. The sensors are provided with an eccentric mounting to adjust the web height at which each sensor begins to operate its associated air valve.

18 Claims, 15 Drawing Figures PATENTEB MR 2 8 1972 WOC SHEET 1 OF 5 INVENTORS ROBERT C. JAMES WALTER H. VOGEL RICHARD H. COCHRANE BY ATTORNEYS PATENTEMAR28 m2 3,652,357

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PATENTEBMARZBIBYE 8.652.357

sum 3 OF 5 B INVENTORS ROBERT C. JAMES WALTER H VOGEL RICHARD H. COCHRANE ATTORNEYS PATENTEDMAR281912 SHEET UF 5 INVENTORS ROBERT C. JAMES a on. 4

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WALTER H. VOGEL RICHARD H. COCHRANE PATENTED MR 2 8 I972 SHEET 5 UF 5 QQE 3 NFQE INVENTORS ROBERT c. JAMES WALTER H. VOGEL RICHARD H. COCHPANE METHOD AND APPARATUS FOR WEB EDGE ALIGNMENT BACKGROUND OF THE INVENTION FIELD OF THE INVENTION This invention relates generally to a new and improved method and apparatus for sensing and controlling the edge position of both edges of a moving web. Specifically, the invention is directed to sensing the edge position of a flexible packaging material which is used to wrap spaced-apart articles positioned on the packaging material. The present invention is particularly suitable for packaging of various different products such as food products, metal parts and the like.

SUMMARY OF THE INVENTION Accordingly, the web edge sensing device of the present invention provides means for continuously controlling the edge position of a moving web. In sensing the edge position of the moving web, it is desirable that the sensing and control apparatus be sensitive to slight variations of the parameter being sensed and yet provide positive control of repositioning the edge when displaced from the desired position.

The method and apparatus of the present invention has particular utility when used in conjunction with a packaging machine wherein a web of flexible packaging material is wrapped about a plurality of spaced-apart articles and sealed along the longitudinal axis thereof near the edges of the film. However, it will be understood that many of the concepts of the present invention may be used for sensing and controlling the edge position of moving webs of any nature.

Therefore, one of the primary objects of the present invention, particularly from a manufacturing standpoint, is to provide a reliable and simple sensing and control apparatus for maintaining the edge positions of a moving web within a desired location as the web moves through the wrapping machine.

Another object of the present invention is to provide a web edge sensing and control apparatus which is sensitive to film imperfections for adjusting and constantly maintaining a desired position of the edges of a moving web being folded in a packaging operation.

Another object of the present invention is to provide a web edge sensing and control device which is efficient and reliable in operation and inexpensive to manufacture.

A further object of the invention is to provide a web edge sensing device which constantly senses and constantly adjusts the position of the edges of a moving web.

A feature of the present invention is the use of a tracking roller which impinges one surface of the web near one edge thereof and opposite a backup surface. The tracking roller rotates about an axis and the axis is pivotable through a plane which is substantially parallel to the direction of movement of the web. The direction of pivotable movement of the axis of the roller will direct movement of the edge of the web.

Accordingly, other objects, features and advantages will be more fully realized and understood from the following detailed description when taken in conjunction with the accompanying drawings wherein like reference numerals throughout the various views of the drawings are intended to designate similar elements and components.

BRIEF DESCRIPTION OF THE DRAWINGS F IG. 1 is a top view of a portion of a packaging machine incorporating the edge sensing and control apparatus of the present invention;

FIG. 2 is a side elevational view of the edge sensor of the present invention;

FIG. 3 is a sectional view taken along the lines IIIIII of FIG. 1;

FIG. 4 is a side elevational view of the portion of the packaging machine shown in FIG. I;

FIG. 5 is a detailed sectional view of the edge control apparatus of the present invention taken along the lines V-V of FIG. 1;

FIG. 6 is a diagrammatical representation of the web edge sensing and film transport device of the present invention;

Fig. 7 is a perspective view showing the relation between the edge control apparatus and the web being controlled;

FIG. 8 is a side elevational view with portions thereof in section illustrating an alternate embodiment of the web edge sensing and control device of the present invention;

Fig. 9 illustrates the pivotable movement of a tracking wheel to control lateral movement of the edge of a moving web;

FIG. 10 is a top plan view of the alternate embodiment shown in FIG. 8; and

FIGS. l1, l2, 13, 14 and 15 illustrate various portions of the sensing and control apparatus of FIGS. 8 and 10.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Seen in FIG. 1 is a top view of a portion of a packaging machine utilizing the web edge sensing and control apparatus of the present invention and is designated generally by reference numeral 10. THe wrapping machine 10 includes a top support 11 which is positioned over a main support table 12. Located at one end of the table 12 is a roller 13 for directing a plastic web 14 through the wrapping machine. The plastic web is supplied from a supply roll (not shown). Articles 16, such as cheese or meat, are delivered at spaced intervals to the web 14 by suitable conveyor and spacing means. As the web 14 moves through the wrapping machine, the edges of the web are folded upwardly by means of a manifold 17 which directs the edges and extended portions of the web to overlie the articles 16. The manifold 17 includes guide plates 18 and 19 so as to be in slidable engagement with the folded inward surface of the web 14. The guide plate 18 includes an idler roller 20 which rotatably engages the inward surface of the web. Similarly, the guide plate 19 includes a idler roller 21 to engage the opposite inward surface of the web 14.

As the web is wrapped about the articles 16, the web engages a support block 22 which continues to wrap the web about the articles in the longitudinal direction. Positioned on opposite sides of the support block 22 are a pair of guide rollers 23 and 24. The guide roller 23 is secured to a rotatable shaft 26 which, in turn, has connected thereto an adjusting device 27 to rotate the shaft 26 and pivot the guide roller 23 about its axis so that the guide roller 23 rotates in an upwardly or downwardly direction relative to the surface of the moving web. Similarly, the guide roller 24 is rotatably connected to a shaft 28 which, in turn, is connected to an adjusting device 29 to rotate the guide roller 24. For example, the guide roller 23 rotates about an axis 30 which is pivotable in a plane substantially parallel to the surface of the web engaging the roller by rotating the shaft 26. So also, the guide roller 24 rotates about an axis 31 which is pivotable through a plane substantially parallel to the surface of the web engaging the roller by rotating the shaft 28.

As the web 14 continues to move through the wrapping machine 10, the upward turned portions of the web are brought closer together by a pair of guides 32 and 33. Secured to the top support 11 is a heat control device 34 which includes a pair of heating bars 36 and 37 for applying heat to the upward turned portions of the moving web and diametrically opposite one another. The heating bars may be operated by an air cylinder 38 or other suitable means. The heated plastic film then moves between a pair of sealing rollers 39 and 40 which apply pressure to the surfaces of the web. The roller 39 is rotatably connected to a carrier 41 such that the axis of the roller is displaced from an adjustably rotatable shaft 42. Similarly, the roller 40 is secured to a carrier 43 such that the axis of the roller 40 is displaced from an adjustably rotatable shaft 44. Therefore, rotating the shafts 42 and 44 not only cause the rollers 39 and 40 to rotate about an axis which can thin!!! Inna be pivotably displaced but also displaces the axis through an arcuate segment.

Accordingly, the packaging machine provides means for directing a plurality of spaced apart articles along a given path and for wrapping the articles with a plastic film. However, during high speed operation of such wrapping machines, it becomes increasingly necessary to control the edge position of the web so that the web will always maintain a given relationship with the folding manifold 17, guides 32 and 33 and heating bars 36 and 37.

According to the present invention, a pair of sensors indicated generally by reference numerals 46 and 47 are provided for sensing the upturned edges of the moving web 14. The sensing device 46 includes an arm 48 which is rotatable about an eccentrically mounted and adjustable pivot 49. The pivot point 49 is provided with an eccentric cam 49a to control the sensing point of the finger 50. By adjusting the cam 49a the pivot point is lowered or raised relative to the table 12. This in turn effects the degree of control of the edge 51 or the web 14. For instance, the cam 49a is adjusted so as to raise the pivot point 49, the edge 51 must be moved to a higher level to develop the same response from the air valve 52. Accordingly, the eccentric cam 49a allows the position of the web to be adjusted relative to the sensor. A similar cam adjustment is provided on the opposite side of the machine at the pivot point 62. At one end of the arm 48 is located a finger 50 which extends transversely of the direction of the moving web and engages the upwardly extending edge 51 of the moving web. Therefore, as the height of the upturned edge changes from a given position, the arm 48 will rotate about the pivot 49 to control the operation of an air valve 52. The air valve 52 receives air pressure through an inlet 53 and controls the amount of air pressure delivered to an outlet 54in response to the position of the pivotable arm 48.

The outlet 54 of the air valve 52 is connected to an inlet 56 of an air cylinder 57. The extensible piston of the air cylinder 57 engages a rotatable bracket 58 which, in turn, is connected to a shaft supporting a tracking roller 59. The tracking roller 59 rotates about an axis 60. Therefore, actuation of the air cylinder 57 causes the rotatable bracket 58 to pivot the axis 60 of the roller 59 in such a manner as to apply an upwardly or downwardly force to the moving web to maintain the edge 56 in a given relation with the wrapping machine. The tracking roller 59 is spring biased against the surface of the web opposite the idler roller 21 so that the web is pinched between the rollers 21 and 59. Therefore, pivotable displacement of the axis 60 shifts the position of the edge of the web.

1 The edge sensor 47 includes an arm 61 which rotates about a pivot 62. The arm 61 includes a finger 63 which engages an edge 64 of the web 14. The finger 63 moves upwardly and downwardly with upward and downward movement of the edge of the web. This causes the arm 47 to rotate and control the operation of an air valve 66. The air valve includes an inlet 67 for receiving pressurized air and an outlet 68 for delivering acontrolled amount of air in response to the position of the finger 63.

The outlet 68 of the air valve 66 is connected to an inlet 69 of an air cylinder 70. The extensible piston of the air cylinder 70 engages a rotatable bracket 71 which, in turn, is connected to a shaft supporting a tracking roller 72. The tracking roller 72 is spring biased against the upwardly outwardly turned surface of the web 14. The tracking roller 72 rotates about an axis 73. Therefore, actuation, of the air cylinder 70 causes the axis 73 to pivot in a plane substantially parallel to the surface of the web engaging the roller. This pivotable movement controls the upward and downward position of the edge of the moving web to maintain the edge within a given relationship within the packaging machine.

The above described control of the edges of the web is constant control. The sensors are constantly sensing the web position and the tracking rollers are constantly urging the edges of the web into a matched condition.

The top support member 1 1 includes a plurality of threaded standards 76, 77, 78 and 79 which provide means for adjusting the position of the top support 11 relative to the main support table 12. For example, the standards 76-79 may include handwheels 80 to manually adjust the top support 1 l.

Seen in FIG. 2 is a detailed showing of the web edge sensing device 46. The pivotable arm 48 has one end thereof engaging the edge 51 of the web 14 via the extended finger 50. However, the other end of the pivotable arm 48 engages an air control device 81 which extends into the air valve 52 to meter the air from the inlet 53 to the outlet 54 in response to the upward position of the edge 51 of web 14. Positioned about the control device 81 is a seal or bellows chamber 82 for providing an air tight seal about the extended control 81. The pivotable arm 48 is dimensioned such that a light gravity bias causes the arm to maintain the finger 50 in contact with the edge 51 of the web 14. However, it well be understood that biasing means may be provided to provide suitable pressure of the finger 50 against the web edge.

Seen in FIG. 3 is a cross section of the upwardly turned web 14 and manifold 17 taken along the lines IIIIII of FIG. 1. The web 14 is formed into a U-shaped tube having a longitudinal opening for receiving the manifold 17. The manifold 17 closes the tube to form a chamber 83 to enclose the articles 16 being wrapped. The manifold 17 may include means for supplying inert gas to the chamber 83 during the wrapping process to evacuate the chamber of contaminated atmosphere thereby reducing the possibility of spoilage. A pair of guide plates 84 and 86 are positioned exteriorly of the U-shaped tube to further guide the web 14 about the articles 16.

FIG. 4 is a side elevational view of the portion of the wrapping machine shown in FIG. 1 and more clearly illustrates the displacement and function of various components. The film 14 originates from a supply roll 87 which is positioned beneath the support table 12. The film is pulled from the supply roll 87 and over the idler roller 13 through the wrapping machine 10. A finger 88 is positioned transversely outwardly of the film 14 so as to initially guide the edges of the film in an upwardly turned direction. Similarly, a second guide finger will be positioned on the opposite side of the machine, not shown. Also seen in FIG. 4 is a rotatable bracket 89 which pivotably adjusts the position of the sealing roller 40. The bracket 89 is similar to the rotatable bracket 58. It will also be noted that the bracket 89 together with the rotatable bracket 29 can be adjusted by automatic actuating means similar to the air cylinder 27. Each of the brackets 29, 58 and 89 are constructed in a similar fashion. For example, the bracket 58 includes a U-shaped slot 90 which receives an extended portion 91 of the extensible element of the air cylinder 57. Therefore, extension and contraction of the air cylinder causes the axis 92 of a shaft 93 to rotate thereby pivoting the tracking roller 59 in such a manner as to position the edge of the moving web in the desired position.

For a better understanding of the operation of the tracking rollers 59 and 72, reference is now made to FIG. 5 which illustrates the operation of the web edge positioning device of the present invention. The shaft 93 is rotatably positioned through a collar 94 which, in turn, is secured to a support member 96 by means of a pin 97 which is spring biased by a spring 98. The support member 96 is part of the top support member 11. A guide 99 is also secured to the support member 96 by means of a bolt 100. The guide block serves to maintain the extensible shaft of the air cylinder 57 in cooperable relation with the U- shaped opening 90 of the rotatable bracket 5 8. The rotatable bracket 58 is secured to the shaft 93 for rotation therewith by a set screw or the like.

The shaft 93 is biased toward the outer surface of the upwardly turned portion of the web 14 by means of a spring 101 which is confined between the collar 94 and a second collar 102. Also secured to the shaft 93 is a support arm 103 which extends from the shaft toward theedge 51 of the web 14.

The tracking roller 59 is secured to the end of the support arm 103 by means of a screw 104. A washer 106 is placed between the support arm 103 and the inner portion of the tracking roller 59. The tracking roller 59 may be formed by a bearing roller having an inner race member 107 which is held in fixed position between the washer 106 and the head of the screw 104. An outer rotatable surface 108 rotates about a plurality of ball bearings 109. The outer surface 108 of the tracking roller 59 is positioned opposite the idler roller 21 supported by the bracket 19 of the manifold 17.

The idler roller 21 is secured to a stub shaft 110 which, in turn, may be press-fit into an aperture 111 of the bracket 19. However, it will be understood that the stub shaft 110 may be secured by any suitable means.

In operation, rotatable movement of the bracket 58 by means of the air cylinder 57, will rotate the shaft 93 about the axis 92. This action will cause the roller 59 to pivot in a plane substantially parallel to the surface of the web engaging the roller. That is, the portion of the roller extending outwardly of the drawing will raise upwardly to lift the edge 51 of the web, and this forward portion of the roller will extend downwardly by rotation of the shaft 93 to move the edge 51 in a downward direction.

Located at the opposite transverse side of the wrapping machine is a support 1 12 which is fixedly secured to the top support member 11. A shaft 1 13 extends through a collar 114 which is secured to the support 112 by means of apin 116 which is spring biased against the collar 114 to engage suitable notching therein by means of a spring 117. A guide block 118 is also secured to the support 112 by means of a bolt 119 to maintain the extensible piston of the air cylinder 170 in cooperable relation with a U-shaped opening 120 of the rotatable bracket 71. The bracket 71 rotates about the axis of shaft 1 13 in the same manner as the bracket 58.

A spring 121 is positioned about the shaft 113 and is located between the collar 114 and a collar 122 to urge the shaft-113 in the direction of the upward turned surface of the web 14. Also secured to the shaft 113 is a support arm 123 which carries the tracking roller 72. The tracking roller is secured to the support arm 123 by means of a screw 124. A spacing washer 126 is positioned between the support arm 123 and the inner portion of the tracking wheel 72.

The tracking roller 72 may comprise a roller bearing having an inner race 127 which is fixedly secured between the head of the screw 124 and the washer 126. The bearing includes a rotatable outer surface 128 which engages the upwardly turned portion of the web 14. Positioned between the inner race 127 and the rotatable portion 128 is a plurality of roller bearings 129.

The idler roller is rotatably secured to a stub shaft 130 which has one end thereof inserted into an aperture 131 of the bracket 18. The portion of the web 14 defining the upwardly turned edge 64 is pinched between the idler roller 20 and the tracking roller 72 in a similar manner as the upwardly turned web portion of edge 51 between idler roller 21 and tracking roller 59. The position of the edge 64 is controlled by rotating the shaft 113 in response to actuation of the air cylinder 70.

Seen in FIG. 6 is a diagrammatic representation of a web edge sensing and control apparatus for forming a tubular foil about a plurality of articles. The outlet 54 of the air valve 52 is connected to the inlet 56 of the air cylinder 57 via a conduit 136. Similarly, the outlet 68 of the air valve 66 is connected to the inlet 69 of air cylinder 70 via a conduit 137. Each of the inlets 53 and 67 of the air valves 52 and 66 respectively are connected to an air supply via a conduit 138. Accordingly, FIG. 6 illustrates the simplicity of the web edge sensing and control system of the present invention.

Seen in FIG. 7 is a perspective detailed view showing the relationship of the upwardly turned portion of the web 14 with that of the tracking wheel 59 and the guide finger 88. A second side guide 139 is provided behind the guide 88 and the sensing finger is positioned therebetween. The guide 88 supported by a crossbar 140 which is secured to the upper support 11 by means of a bolt 141. The web 14 is formed upwardly and then folded-over by means of the guide plate 84.

The upwardly extending portion of the web 14 is then drawn together by means of the tapered shape of manifold 17 and the guides 32 and 33.

FIGS. 8 and 10 illustrate a modified form of the web edge sensing and control apparatus of the present invention. As best seen in FIG. 8, the web 14 is folded-over such that the edges 151 and 152 are facing one another and displaced one above the other. The edge 151 is guided under a guide plate 153, and the edge 152 is above the guide plate 153.

As the web 14 moves in the direction of the arrowed line 155, both edges 151 and 152 of the web 14 are over a backing plate 154. It will be noted that the edges 151 and 152 are displaced laterally one from the other so as to be staggered in the cross machine direction. A spacer 156 is disposed between the edge portions 151 and 152 of the web 14. A second backing I spacer 157 is disposed between the folded-over portions of the web 14. The edge portion 152 of the web 14 is then tucked under a guide 159 thereby joining the edge portion 152 with the edge portion 153.

The edge portions 151 and 152 are then sealed together by a heat sealing device 160 which is actuated by an air cylinder 161. The air cylinder 161 includes an extensible piston 162 which is connected to one end of a lever 163 which, in turn, is connected to a bracket 164 for supporting the heat sealing device 160. During the operation of the wrapping machine, a control signal will actuate the air cylinder 161 to lower the heating unit 160 in heating relation with the folded-over portions 151 and 152 of the web 14 for heat sealing thereof.

According to the present invention, a tracking wheel 166 rotates about an axis 167 and engages one surface of the web 14 near the edge 151. The tracking wheel 166 is rotatably secured to a support 168 which, in turn, is secured to a shaft 169. The shaft 169 rotates about its axis in response to control signals indicative of the position of edge 151 thereby providing a corrective force to laterally slide or move the edge of the film to a desired position.

The tracking wheel is spring biased toward the surface of the film by means of a spring 170 which is positioned between the support arm 168 and a collar 171. The shaft 169 is connected to a rotatable bracket 172 at one end thereof and a U- shaped slot of the bracket engages an extended portion 173 of the extensible piston of an air cylinder 176. The extensible piston of the air cylinder 176 moves in a support housing 174 in the usual manner.

' The web edge sensing device includes an arm 177 which is pivotable about a pin 178 located intermediate the two ends of the arm. The lower end of the arm includes a finger 179 which engages the edge 151 of the web 14 to sense the lateral position of the edge. Movement of the edge 151 causes the arm 177 to pivot about the pin and actuate a control device 180 which forms part of an air valve 181. The control device 180 meters air flow through the air valve 181 in response to movement ofthe arm 177.

The air valve 181 is connected to an air supply via a conduit 182 and the metered or controlled air flow from the air valve 181 is delivered to the air cylinder 176 via a conduit 183.

A second tracking wheel 184 rotates about an axis 185 which, in turn, is secured to a support bracket 186. The support bracket 186 is connected to a shaft 187 which has the other end thereof connected to a rotatable bracket 188. The bracket 188 includes a U-shaped slot for receiving the end of an extensible piston 190 of an air cylinder 191.

A second edge sensing arm 192 pivots about a pin 193 and has a finger 194 located at one end of the arm and engaging the edge 152 of the web 15. The other end of arm 192 is connected to a metering rod or control 196 of an air valve 197. The air valve 197 is connected to an air supply via a conduit 198. The controlled air flow from the valve 197 is delivered to the air cylinder 191 via a conduit 199.

The operation of the web edge sensing and control system shown in FIGS. 8 and 10 is substantially similar to that shown in FIG. 5, the only difference being that the tracking wheels 166 and 184 are positioned one in front of the other rather seen in FIG. 9. The sensing arm 192 and tracking wheel 184 operate in the same manner as described hereinabove but control the position of edge 152.

For a better understanding of the cooperation between the edge portions 151 and 152 of the web 14 and the guide plates 153,154, 156, 157, 158 and 159, reference is now made to the sequence of FIGS. 11, 12, 13, 14 and 15. Seen in FIG. 11, the

I edge portion 151 passes over the guide plate 154 while the edge portion 152 passes over the guide plate 153. The guide plate 154 serves as a backup plate for the tracking wheel 166. As the web advances toward the sealing unit 160, the edge portion 152 is moved laterally, to the right, as seen in FIG. 12,

over the guide plate 156. As the web moves further toward the heating unit 160 the edge 152 is guided between the guide plates 157 and 158. As seen in FIG. 14, the guide plate 157 serves as a backing plate for the tracking wheel 184. The edge portion 152 then engages the finger 194 of the sensing arm 192 to control the actuation of the air cylinder 197. Thereafter, the edge portions 151 and 152 are guided between the guide plates 154 and 159 and therefrom to a raised portion 200 of the plate 154 where the edges are heat sealed together by the heating unit 160.

We claim: 1. An apparatus for controlling the edge position of a moving web, comprising:

a sensor for sensing the edge position of the moving web; a control connected to said sensor for developing control signals indicative of the edge position of the moving web; a first roller rotatably positioned adjacent one edge of the web, said first roller being rotatable about an axis perpendicular to the direction of movement of the web; a second roller rotatably positioned adjacent the other edge of the web, means for arranging the edges of the web so that relative lateral movement between the edges is developed when one of said rollers is pivoted about its axis, and an actuator connected between said control and at least one of said rollers and being responsive to said control signals to pivot the axis of said one roller for developing relative movement between the edges thereby directing the edges to a corrective position, said pivot comprising an eccentrically mounted and adjustable pivot. 2. An apparatus for controlling the edge position of a moving web, comprising:

means for directing a moving web along a path; means engaging the moving web for rolling the web to form a continuous U-shaped tube having an axial opening formed by the spaced-apart edges of the moving web; surface means engaging the inner portion of the U-shaped tube near the edges of the web; a first sensor for sensing one edge position of the moving web; a second sensor for sensing the other edge position of the moving web; a first control connected to said first sensor for developing first control signals indicative of said one edge position of the moving web; a second control connected to said second sensor for developing second control signals indicative of the other edge position of the moving web;

a first roller rotatably positioned against the outer surface of the U-shaped tube near said one edge and opposite said surface means,

a second roller rotatably positioned against the outer surface of the U-shaped tube and adjacent the other edge of the web and opposite said surface means, and a first actuator connected between said first control and said first roller and responsive to said first control signals to pivot the axis the said first roller for directing said one edge of the moving web to a corrective position; and

a second actuator connected between said second control and said second roller and responsive to said second control signals to pivot the axis of said second roller for directing the other edge position of the moving web to a corrective position.

3. An apparatus for controlling the edge position of a moving web according to claim 2 wherein said first sensor includes a first arm having two ends; a first finger secured to one end of said first arm, said first finger engaging said one edge of the moving web; a pivot intermediate the two ends of said first arm to allow said first arm to pivot thereabout in response to the edge position of said one edge of the moving web; the other end of said first arm engaging said first control to develop said first control signal in response to the pivoting of said first arm; and wherein said second sensor includes a second arm having two ends; a second finger secured to one end of said second arm, said second finger engaging said other edge of the moving web; a pivot intermediate the two ends of said second arm to allow said second arm to pivot thereabout in response to the edge position of said other edge of the moving web; the other end of said second arm engaging said second control to develop said second control signals in response to the pivoting of said second arm.

4. An apparatus for controlling the edge position of a moving web according to claim 3 wherein each of said arms are mounted on an eccentric and adjustable pivot.

5. An apparatus for controlling the edge position of a moving web according to claim 2 wherein said first and second controls each include an air valve for controlling air pressure in response to the edge position of the respective edges of the moving web, and wherein said first and second actuators each include an air cylinder responsive to the controlled air pressure of the respective air valves for pivoting the axes of said first and second rollers to direct said one edge and said other edge to corrective positions.

6. An apparatus for controlling the edge position of a moving web according to claim 2 further including means for converging the inner surfaces of said U-shaped tube near the edges thereof to engage said inner surfaces to close the opening of said U-shaped tube thereby forming a closed tube.

7. An apparatus for controlling the edge position of a moving web according to claim 6 further including a heater sealably engaging the outer surface of the U-shaped tube near the edges thereof to cause the inner surfaces of the tube to be heatsealed thereby permanently closing the tube.

8. An apparatus for controlling the edge position of a mov ing web according to claim 2 further including means for folding over said one edge of the moving web with said other edge of said moving web to close the U-shaped tube to form a closed tube.

9. An apparatus for controlling the edge position of a moving web according to claim 8 further including a heat scalable means engaging the folded-over edges of the tube to heat-seal the tube near the edges thereby permanently sealing the tube.

10. An apparatus for controlling the edge position of a moving web, comprising:

means for directing the moving web along a given path;

means for rolling the web into a U-shaped tube;

first means for sensing one edge position of the U-shaped tube;

second means for sensing the other edge position of the U- shaped tube;

means connected to said first and second means for developing first and second control signals indicative of said one edge position and said other edge position respectively;

surface means engaging the inner surface of said U-shaped tube near the edges thereof;

first roller means rotatably positioned against the outer surface of said U-shaped tube adjacent said one edge thereof and opposite said surface means, second roller means rotatably positioned against the outer surface of the U- shaped tube and adjacent the other edge thereof and opposite said surface means, and first and second actuator means connected between said control means and said first and second rollers respectively and responsive to said first and second control signals to pivot said first and second rollers about their axes for directing said one edge and said other edge of the web to corrective positions.

1 1. An apparatus for controlling the edge position of a moving web according to claim 10 further including means for forming the U-shaped tube into a closed tube.

12. An apparatus for controlling the edge position of a moving web according to claim 11 wherein said means for forming said U-shaped tube into a closed tube include guide means for directing the inner surface near the edges of the tube together such that the inner surface near each of the edges engage one another.

13. A method of controlling the edge position of a moving web comprising the steps of:

arranging the web in such a way as to permit relative transverse movement between the edges thereof;

sensing one edge position of the moving web;

sensing the other edge position of the moving web;

' developing first control signals indicative of said one edge position of the moving web;

developing second control signals indicative of the other edge position of the moving web;

engaging one side of the moving web with a surface adjacent said one and said other edges;

engaging the other side of the moving web adjacent said one edge with a roller rotatable about an axis;

engaging said other side of the web adjacent said other edge with a second roller which is rotatable about an axis perpendicular to the direction of the moving web;

actuating said first and second rollers in response to said first and second control signals respectively to pivot the axis of said first and second rollers; and

moving the edges transversely relative to each other for directing said one edge and said other edge of the moving web to corrective positions responsive to said first and second control signals, further including the step of heatsealing the formed tube near the edges thereof to permanently seal the longitudinal edge of the tube.

14. A method of controlling the position of a moving web according to claim 13 further including the step of heat-sealing the formed tube near the edges thereof to permanently seal the longitudinal edge of the tube.

15. In a machine having a traveling web, a sensor for regulating the edge position of the web comprising:

a sensor am having a first portion thereof contacting the edge of the web to be controlled and a second portion thereof coupled to a signal generator for developing a signal indicative of the instantaneous position of the edge of the web being controlled, said sensor arm being pivotally supported intermediate said first and second portions and said pivot point having an eccentric cam associated therewith for regulating the degree of control of said sensor on the edge position of said web.

16. A machine in accordance with claim 15 wherein means are provided to form said web into a U-shape, and wherein a pair of said sensors are provided to sense both edges of the U.

17. A machine in accordance with claim 16 wherein each of said sensors have an eccentric cam support at the pivot points thereof.

18. In a machine having a travelling web, a sensor for regulating the edge position of the web comprising:

a sensor having a finger portion for contacting an edge of the web and an actuator portion,

signal means, said actuator portion continuously coupled to said signal means and constantly developing a signal indicative of the position of the edge of the web being sensed, and transducer means utilizing said signal to constantly move said edge to a corrective position,

said web being U-shaped and means being provided to con stantly sense both edges of the U-shaped web and to constantly urge the edges into a corrective position. 

1. An apparatus for controlling the edge position of a moving web, comprising: a sensor for sensing the edge position of the moving web; a control connected to said sensor for developing control signals indicative of the edge position of the moving web; a first roller rotatably positioned adjacent one edge of the web, said first roller being rotatable about an axis perpendicular to the direction of movement of the web; a second roller rotatably positioned adjacent the other edge of the web, means for arranging the edges of the web so that relative lateral movement between the edges is developed when one of said rollers is pivoted about its axis, and an actuator connected between said control and at least one of said rollers and being responsive to said control signals to pivot the axis of said one roller for developing relative movement between the edges thereby directing the edges to a corrective position, said pivot comprising an eccentrically mounted and adjustable pivot.
 2. An apparatus for controlling the edge position of a moving web, comprising: means for directing a moving web along a path; means engaging the moving web for rolling the web to form a continuous U-shaped tube having an axial opening formed by the spaced-apart edges of the moving web; surface means engaging the inner portion of the U-shaped tube near the edges of the web; a first sensor for sensing one edge position of the moving web; a second sensor for sensing the other edge position of the moving web; a first control connected to said first sensor for developing first control signals indicative of said one edge position of the moving web; a second control connected to said second sensor for developing second control signals indicative of the other edge position of the moving web; a first roller rotatably positioned against the outer surface of the U-shaped tube near said one edge and opposite said surface means, a second roller rotatably positioned against the outer surface of the U-shaped tube and adjacent the other edge of the web and opposite said surface means, and a first actuator connected between said first control and said first roller and responsive to said first control signals to pivot the axis the said first roller for directing said one edge of the moving web to a corrective position; and a second actuator connected between said second control and said second roller and responsive to said second control signals to pivot the axis of said second roller for directing the other edge position of the moving web to a corrective position.
 3. An apparatus for controlling the edge position of a moving web according to claim 2 wherein said first sensor includes a first arm having two ends; a first finger secured to one end of said first arm, said first finger engaging said one edge of the moving web; a pivot intermediate the two ends of said first arm to allow said first arm to pivot thereabout in response to the edge position of said one edge of the moving web; the other end of said first arm engaging said first control to develop said first control signal in response to the pivoting of said first arm; and wherein said second sensor includes a second arm having two ends; a second finger secured to one end of said second arm, said second finger engaging said other edge of the moving web; a pivot intermediate the two ends of said second arm to allow said second arm to pivot thereabout in response to the edge position of said other edge of the moving web; the other end of said second arm engaging saId second control to develop said second control signals in response to the pivoting of said second arm.
 4. An apparatus for controlling the edge position of a moving web according to claim 3 wherein each of said arms are mounted on an eccentric and adjustable pivot.
 5. An apparatus for controlling the edge position of a moving web according to claim 2 wherein said first and second controls each include an air valve for controlling air pressure in response to the edge position of the respective edges of the moving web, and wherein said first and second actuators each include an air cylinder responsive to the controlled air pressure of the respective air valves for pivoting the axes of said first and second rollers to direct said one edge and said other edge to corrective positions.
 6. An apparatus for controlling the edge position of a moving web according to claim 2 further including means for converging the inner surfaces of said U-shaped tube near the edges thereof to engage said inner surfaces to close the opening of said U-shaped tube thereby forming a closed tube.
 7. An apparatus for controlling the edge position of a moving web according to claim 6 further including a heater sealably engaging the outer surface of the U-shaped tube near the edges thereof to cause the inner surfaces of the tube to be heatsealed thereby permanently closing the tube.
 8. An apparatus for controlling the edge position of a moving web according to claim 2 further including means for folding over said one edge of the moving web with said other edge of said moving web to close the U-shaped tube to form a closed tube.
 9. An apparatus for controlling the edge position of a moving web according to claim 8 further including a heat sealable means engaging the folded-over edges of the tube to heat-seal the tube near the edges thereby permanently sealing the tube.
 10. An apparatus for controlling the edge position of a moving web, comprising: means for directing the moving web along a given path; means for rolling the web into a U-shaped tube; first means for sensing one edge position of the U-shaped tube; second means for sensing the other edge position of the U-shaped tube; means connected to said first and second means for developing first and second control signals indicative of said one edge position and said other edge position respectively; surface means engaging the inner surface of said U-shaped tube near the edges thereof; first roller means rotatably positioned against the outer surface of said U-shaped tube adjacent said one edge thereof and opposite said surface means, second roller means rotatably positioned against the outer surface of the U-shaped tube and adjacent the other edge thereof and opposite said surface means, and first and second actuator means connected between said control means and said first and second rollers respectively and responsive to said first and second control signals to pivot said first and second rollers about their axes for directing said one edge and said other edge of the web to corrective positions.
 11. An apparatus for controlling the edge position of a moving web according to claim 10 further including means for forming the U-shaped tube into a closed tube.
 12. An apparatus for controlling the edge position of a moving web according to claim 11 wherein said means for forming said U-shaped tube into a closed tube include guide means for directing the inner surface near the edges of the tube together such that the inner surface near each of the edges engage one another.
 13. A method of controlling the edge position of a moving web comprising the steps of: arranging the web in such a way as to permit relative transverse movement between the edges thereof; sensing one edge position of the moving web; sensing the other edge position of the moving web; developing first control signals indicative of said one edge position of the moving web; DEVELOPING second control signals indicative of the other edge position of the moving web; engaging one side of the moving web with a surface adjacent said one and said other edges; engaging the other side of the moving web adjacent said one edge with a roller rotatable about an axis; engaging said other side of the web adjacent said other edge with a second roller which is rotatable about an axis perpendicular to the direction of the moving web; actuating said first and second rollers in response to said first and second control signals respectively to pivot the axis of said first and second rollers; and moving the edges transversely relative to each other for directing said one edge and said other edge of the moving web to corrective positions responsive to said first and second control signals, further including the step of heat-sealing the formed tube near the edges thereof to permanently seal the longitudinal edge of the tube.
 14. A method of controlling the position of a moving web according to claim 13 further including the step of heat-sealing the formed tube near the edges thereof to permanently seal the longitudinal edge of the tube.
 15. In a machine having a traveling web, a sensor for regulating the edge position of the web comprising: a sensor arm having a first portion thereof contacting the edge of the web to be controlled and a second portion thereof coupled to a signal generator for developing a signal indicative of the instantaneous position of the edge of the web being controlled, said sensor arm being pivotally supported intermediate said first and second portions and said pivot point having an eccentric cam associated therewith for regulating the degree of control of said sensor on the edge position of said web.
 16. A machine in accordance with claim 15 wherein means are provided to form said web into a U-shape, and wherein a pair of said sensors are provided to sense both edges of the U.
 17. A machine in accordance with claim 16 wherein each of said sensors have an eccentric cam support at the pivot points thereof.
 18. In a machine having a travelling web, a sensor for regulating the edge position of the web comprising: a sensor having a finger portion for contacting an edge of the web and an actuator portion, signal means, said actuator portion continuously coupled to said signal means and constantly developing a signal indicative of the position of the edge of the web being sensed, and transducer means utilizing said signal to constantly move said edge to a corrective position, said web being U-shaped and means being provided to constantly sense both edges of the U-shaped web and to constantly urge the edges into a corrective position. 